Crisis Squad 1:
3 Crisis Battlesuits, all with twin-linked flamers, drone controller, 2 gun drones - 153 points
This unit will be absolutely deadly against light infantry, such as Guardsmen, Orks, and Tyranids, and will even put a dent in Marines. It has a grand total of 12 wounds, and it isn't super expensive, either! the best way to use this, is to leave an obvious hole in your lines, and then when the enemy sends a horde to exploit it, you Deep Strike this beast right in front of it, and then flame their brains out. Once this is done, you usually want to jump behind cover.
Crisis Squad 2:
3 Crisis Battlesuits, all with Missile Pod, Plasma Rifle, targeting array, hard-wired multi-tracker, hard wired drone controller, 1 gun drone - 246 points
This unit, though expensive, will absolutely devastate both infantry and tanks with too many accurate, high-strength shots. best use for this is to Deep Strike them next to a monstrous creature, take out the beastie in question, and then wade further into the fight. The other great thing about these units is that neither of them is terrible in combat, with strength 5 and 2 attacks, as well as a healthy 3+ armor save. Taking both of these in the same army, combined with a Commander with his bodyguard, some Fire Warriors in Devilfish, a couple of Broadsides, and a Sky Ray, and you have a problem on your hands.